Question Ethernet Disconnect Issue

Jul 19, 2021
Provide us with the make and model of your laptop (if applicable) -Custom built PC w/ the following specs: i7 11600K OC to 5.1 GHz, Corsair Dominator 3333MHz RAM (32 GB) running in XMP II mode, Asus ROG STRIX Z590-A, Nvidia RTX 2080 Ti. The CPU and processor are in a custom loop. 1200W Rosewill lightning PSU, Samsung 970 evo 500 GB, Samsung 980 1TB (main OS), WD 4TB Gold (backup drive), Samsung 850 and 840 EVO (both 1TB and used for games). My ISP is Comcast/Xfinity
  • Provide us with the make and model of your router - I have one switch, but I'm not connected to it. My dad uses it to get his own connections.
  • Provide us with the make and model of your modem - Xfinity Xfi modem
  • Provide us with the exact specifications of your PC (if applicable) including:
I'm running on Windows 10 Pro with ALL of the latest updates. My computer is directly connected to the modem with a CAT6 cable, which is routed through the ceiling to the modem itself. I get 400MB/s down and 10 MB/s up speeds. I'm using the intel ethernet 1225-v network adapter. There is no NAS or anything connected to the line. There are 3 cell phones connected to wifi at all times, 1 tablet, and two TVs.

My problem description:

Recently I've built a new system.. the one you see the specs listed above for. It's ran great. No issues whatsoever. I've been gaming, streaming, and creating YouTube videos for about 2 months with this machine. About a week and a half ago I had an issue where my ethernet was completely dropping out during my streams. I power cycled the modem and it didn't fix it. Comcast said they noticed an issue from their end as well but that it would be 4-5 days before they could get a technician to my house. Apparently there was a problem outside. The tech finally came, upgraded our modem as a courtesy to the Xfinity Xfi modem. I thought the issue was fixed but nothing changed. I would get completely random disconnects, sometimes one after another and other times 8 hours without one. I found out that our internet wasn't completely going down. I could still connect on my phone to Wi-FI (which I should have tried earlier in this process being an IT guy) and I could also connect my desktop to Wi-Fi as it's built into my motherboard. The only way I could get the ethernet to work properly again was to either A.) uninstall the ethernet controller completely from my pc and let it reinstall or ..

B.) run the following commands in an elevated command prompt

netsh int tcp set heuristics disabled
netsh int tcp set global autotuninglevel=disabled
netsh int tcp set global rss=enabled
netsh winsock reset
netsh int ip reset
ipconfig /release
ipconfig /renew
ipconfig /flushdns

This would make my ethernet "remember" that it was connected again instead of saying "no internet". But then the issue just happens over again whenever it seems to feel like it. I don't like gaming or streaming on Wi-Fi and to be honest I pay a lot of money for these things so I don't want to use Wi-Fi anyways. I thought it was somehow possible that either my ethernet cable or RJ45 jack in my motherboard were damaged. I can't find an issue with either one.. no bent or broken pins. I don't know at this point what's going on and it's driving me insane.. I'm tired of my streams cutting off and having to restart and do the troubleshooting methods repeatedly. I would try to connect another CAT cable to the modem but I don't have one long enough to go through the ceiling and Comcast gave us a really tiny one. I doubt it's the cable but I can't completely rule that out. I would send the motherboard back if the RJ45 connector failed on the board, but taking apart my watercooling setup AGAIN after taking it out of the last system, building this new pc, and installing that watercooling system in this machine will be a nightmare I'd not care to repeat.

I will note though that my ethernet NEVER cuts out when I'm just browsing the internet, watching twitch streams, or youtube videos. I legitimately have tried every single possible thing to figure out the issue and it's driving me completely INSANE. If I can't find a solution in this forum I'm going to try ordering a LAN card and a CAT7 cable.
Jul 19, 2021
I'd also like to add some information. I don't believe the modem is at fault at all because this issue was present with both the old and the new modems.


Make and model information: modem, router, switch?


"My computer is directly connected to the modem with a CAT6 cable, which is routed through the ceiling to the modem itself. "

Normal home networks are generally set up per the following line diagram ( ----> representing an Ethernet cable).

ISP === (Coax, DSL, fiber) ===> Modem ----->[WAN Port]Router [LAN Ports] -----> wired devices/switches and ~~~ > wireless devices.

Why is your computer being connected to the modem and not to the router?

Feel free to edit and correct my line diagram as necessary to show your network. Include the switch and other devices.

And forget about Cat 7 cable. Cat 5e or Cat 6 should be fine. Just ensure that the cable is round (not flat), all copper (not copper clad aluminum) and 22-24 AWG. Lots of fake and substandard cables being sold.